Trial hears drink and drugs rather than mental disorder had role to play in Tallaght murder

A murder trial has heard psychiatric evidence drink and drugs rather than a mental disorder may explain Dublin woman Tanya Doyle's state of mind when she stabbed her husband over 60 times.

The 40 year old admits killing engineer Paul Byrne at their home in Pairc Gleann Trasna, Aylesbury in Tallaght, Dublin on September 4 2009, but denies his murder.

Psychiatric experts who interviewed Tanya Doyle differ in their views about her state of mind when she stabbed her husband to death.

Defence witness consultant Dr Paul O'Connell told the jury he believed the 40 year old was not insane but did have schizoaffective disorder that would diminish her responsibility for the killing.

Today prosecution witness Prof Harry Kennedy from the Central Mental Hospital charted her use of cocaine, alcohol and benzodiazepines and said drugs and drink could explain her beliefs at the time that she was being persecuted by her husband and others.

Intoxication does not amount to a defence under the Criminal Insanity Act.

He noted Tanya Doyle appeared to know she would not stand to gain financially if she pursued a divorce and that she seemed to have been prompted by feelings of jealousy when she stabbed Paul Byrne three years earlier after attending Stringfellows.